:root {
  --bg: #f4f6f9;
  --surface: #ffffff;
  --ink: #1b2430;
  --muted: #64707f;
  --line: #dde3ea;
  --primary: #1f4e8c;
  --primary-dark: #163a69;
  --primary-soft: #e8f0fb;
  --ok: #1d7a4a;
  --ok-soft: #e3f4ea;
  --bad: #b3261e;
  --bad-soft: #fbe9e7;
  --warn: #8a5a00;
  --warn-soft: #fff4d9;
  --radius: 8px;
  --shadow: 0 1px 2px rgba(20, 30, 50, .06), 0 4px 14px rgba(20, 30, 50, .05);
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font: 15px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", sans-serif;
}
h1, h2, h3 { line-height: 1.3; margin: 0 0 .6em; }
h1 { font-size: 1.5rem; } h2 { font-size: 1.2rem; } h3 { font-size: 1.05rem; }
a { color: var(--primary); }
.muted { color: var(--muted); }
.small { font-size: .85rem; }
.hidden { display: none !important; }

/* ----- Header ----- */
.topbar { background: var(--primary-dark); color: #fff; }
.topbar-inner {
  max-width: 1180px; margin: 0 auto; padding: 0 20px; height: 56px;
  display: flex; align-items: center; gap: 16px;
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 600; font-size: 1.05rem; color: #fff; text-decoration: none; }
.brand img { width: 28px; height: 28px; }
.topbar .spacer { flex: 1; }
.topbar .who { font-size: .85rem; opacity: .85; }
.topbar a.link, .topbar button.link {
  color: #fff; background: none; border: 0; cursor: pointer; font: inherit; font-size: .9rem;
  opacity: .9; text-decoration: none; padding: 6px 8px; border-radius: 6px;
}
.topbar a.link:hover, .topbar button.link:hover { background: rgba(255,255,255,.14); opacity: 1; }

.container { max-width: 1180px; margin: 0 auto; padding: 24px 20px 60px; }

/* ----- Tabs ----- */
.tabs { display: flex; gap: 4px; border-bottom: 1px solid var(--line); margin-bottom: 22px; overflow-x: auto; }
.tab {
  background: none; border: 0; border-bottom: 3px solid transparent; padding: 10px 16px; cursor: pointer;
  font: inherit; color: var(--muted); white-space: nowrap;
}
.tab:hover { color: var(--ink); }
.tab.active { color: var(--primary); border-bottom-color: var(--primary); font-weight: 600; }

/* ----- Cards / layout ----- */
.card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); padding: 20px; }
.card + .card { margin-top: 18px; }
.grid { display: grid; gap: 16px; align-items: stretch; }
.grid > .card, .grid > .card + .card { margin-top: 0; }
.grid.cols-3 > .card { display: flex; flex-direction: column; }
.grid.cols-3 > .card .btn.block { margin-top: auto; }
.grid.cols-3 { grid-template-columns: repeat(auto-fill, minmax(290px, 1fr)); }
.grid.kpis { grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); }
.grid.two { grid-template-columns: repeat(auto-fit, minmax(420px, 1fr)); }
.row { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
.row.between { justify-content: space-between; }
.stack > * + * { margin-top: 12px; }

.kpi { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px 18px; box-shadow: var(--shadow); }
.kpi .label { color: var(--muted); font-size: .85rem; }
.kpi .value { font-size: 1.8rem; font-weight: 700; line-height: 1.2; margin-top: 4px; }
.kpi.ok .value { color: var(--ok); } .kpi.bad .value { color: var(--bad); }

/* ----- Forms ----- */
label.field { display: block; font-size: .88rem; color: var(--muted); }
label.field > span { display: block; margin-bottom: 4px; }
input[type=text], input[type=email], input[type=password], input[type=number], input[type=search], select, textarea {
  width: 100%; padding: 9px 11px; border: 1px solid #c4ccd6; border-radius: 6px; background: #fff;
  font: inherit; color: var(--ink);
}
input:focus, select:focus, textarea:focus, button:focus-visible { outline: 2px solid var(--primary); outline-offset: 1px; border-color: var(--primary); }
input[type=file] { font: inherit; }

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px; padding: 9px 16px; border-radius: 6px;
  border: 1px solid var(--primary); background: var(--primary); color: #fff; cursor: pointer; font: inherit; font-weight: 500;
}
.btn:hover { background: var(--primary-dark); }
.btn:disabled { opacity: .55; cursor: not-allowed; }
.btn.secondary { background: #fff; color: var(--primary); }
.btn.secondary:hover { background: var(--primary-soft); }
.btn.danger { background: #fff; color: var(--bad); border-color: var(--bad); }
.btn.danger:hover { background: var(--bad-soft); }
.btn.sm { padding: 4px 10px; font-size: .85rem; }
.btn.block { width: 100%; }

/* ----- Table ----- */
.table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: var(--radius); background: #fff; }
table { border-collapse: collapse; width: 100%; font-size: .9rem; }
th, td { padding: 9px 12px; text-align: left; border-bottom: 1px solid var(--line); vertical-align: middle; }
th { background: #f0f3f7; color: #3a4553; font-weight: 600; white-space: nowrap; }
tr:last-child td { border-bottom: 0; }
td input[type=number] { width: 80px; padding: 5px 8px; }
td input[type=text] { padding: 5px 8px; min-width: 140px; }

/* ----- Badges ----- */
.badge { display: inline-block; padding: 2px 10px; border-radius: 999px; font-size: .78rem; font-weight: 600; }
.badge.ok { background: var(--ok-soft); color: var(--ok); }
.badge.bad { background: var(--bad-soft); color: var(--bad); }
.badge.warn { background: var(--warn-soft); color: var(--warn); }
.badge.gray { background: #eceff3; color: var(--muted); }

/* ----- Login ----- */
.auth-wrap { min-height: 100vh; display: grid; place-items: center; padding: 20px; }
.auth-card { width: 100%; max-width: 420px; }
.auth-card .logo { text-align: center; margin-bottom: 18px; }
.auth-card .logo img { width: 56px; height: 56px; }
.auth-card .logo h1 { margin: 8px 0 2px; }
.msg { padding: 10px 12px; border-radius: 6px; font-size: .9rem; margin-top: 12px; }
.msg.err { background: var(--bad-soft); color: var(--bad); }
.msg.info { background: var(--primary-soft); color: var(--primary-dark); }
.msg.ok { background: var(--ok-soft); color: var(--ok); }
.banner { background: var(--warn-soft); color: var(--warn); padding: 10px 20px; text-align: center; font-size: .9rem; }

/* ----- Exam ----- */
.exam-layout { display: grid; grid-template-columns: 1fr 260px; gap: 18px; align-items: start; }
.exam-head { position: sticky; top: 0; z-index: 5; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 12px 18px; margin-bottom: 16px; }
.timer { font-variant-numeric: tabular-nums; font-size: 1.3rem; font-weight: 700; color: var(--primary); }
.timer.low { color: var(--bad); }
.q-text { font-size: 1.08rem; margin-bottom: 16px; white-space: pre-wrap; }
.opt {
  display: flex; gap: 10px; align-items: flex-start; padding: 11px 14px; border: 1px solid var(--line); border-radius: 6px;
  margin-bottom: 10px; cursor: pointer; background: #fff;
}
.opt:hover { border-color: var(--primary); background: var(--primary-soft); }
.opt.selected { border-color: var(--primary); background: var(--primary-soft); }
.opt input { margin-top: 4px; }
.noselect { user-select: none; -webkit-user-select: none; }
.qnav { display: grid; grid-template-columns: repeat(5, 1fr); gap: 6px; }
.qnav button { padding: 8px 0; border: 1px solid var(--line); background: #fff; border-radius: 6px; cursor: pointer; font: inherit; }
.qnav button.answered { background: var(--primary-soft); border-color: var(--primary); color: var(--primary-dark); }
.qnav button.current { outline: 2px solid var(--primary); }

.result-hero { text-align: center; padding: 32px 20px; }
.result-hero .score { font-size: 3.4rem; font-weight: 800; line-height: 1.1; }
.result-hero.pass .score, .result-hero.pass .verdict { color: var(--ok); }
.result-hero.fail .score, .result-hero.fail .verdict { color: var(--bad); }
.verdict { font-size: 1.3rem; font-weight: 700; margin-top: 6px; }

.review-q { border-left: 4px solid var(--line); padding-left: 14px; margin-bottom: 22px; }
.review-q.right { border-left-color: var(--ok); }
.review-q.wrong { border-left-color: var(--bad); }
.review-opt { padding: 6px 10px; border-radius: 6px; margin: 4px 0; border: 1px solid transparent; }
.review-opt.correct { background: var(--ok-soft); border-color: var(--ok); }
.review-opt.mine-wrong { background: var(--bad-soft); border-color: var(--bad); }
.explain { background: var(--warn-soft); border-radius: 6px; padding: 8px 12px; margin-top: 8px; white-space: pre-wrap; }

/* ----- Charts ----- */
.bar-row { display: grid; grid-template-columns: 150px 1fr 64px; gap: 10px; align-items: center; margin: 10px 0; font-size: .9rem; }
.bar-track { background: #e9edf2; height: 14px; border-radius: 7px; overflow: hidden; }
.bar-fill { height: 100%; background: var(--primary); border-radius: 7px; }
.bar-fill.ok { background: var(--ok); } .bar-fill.bad { background: var(--bad); }
.chart-svg { width: 100%; height: auto; display: block; }
.legend { display: flex; gap: 16px; font-size: .82rem; color: var(--muted); margin-top: 6px; }
.legend i { display: inline-block; width: 10px; height: 10px; border-radius: 2px; margin-right: 5px; }

/* ----- Import ----- */
.dropzone { border: 2px dashed #b8c3d1; border-radius: var(--radius); padding: 20px; background: #fafbfd; }
.err-list { max-height: 160px; overflow: auto; font-size: .85rem; color: var(--bad); margin: 8px 0 0; padding-left: 18px; }
pre.sample { background: #f0f3f7; padding: 12px; border-radius: 6px; overflow: auto; font-size: .82rem; }

/* ----- Toast ----- */
#toast-host { position: fixed; right: 18px; bottom: 18px; z-index: 50; display: flex; flex-direction: column; gap: 8px; }
.toast { background: #1b2430; color: #fff; padding: 10px 16px; border-radius: 6px; box-shadow: var(--shadow); max-width: 340px; }
.toast.err { background: var(--bad); }
.toast.ok { background: var(--ok); }

@media (max-width: 860px) {
  .exam-layout { grid-template-columns: 1fr; }
  .grid.two { grid-template-columns: 1fr; }
  .bar-row { grid-template-columns: 100px 1fr 54px; }
  .topbar .who { display: none; }
}